1. Field of the Invention
This invention relates to a grid system for a suspended ceiling of the kind comprising mutually spaced main runners of inverted T-profile suspended by means of hangers at the web of the T-profile, the flanges of the T-profile forming support surfaces for tiles, apertures punched at regular spacing in the web of the T-profile registering transversely of the main runners, and mutually spaced cross spacers engaging the main runners and defining the spacing therebetween.
The tiles demountably supported by the grid system conceal this system, the linear joints between adjacent tiles being visible as a rectangular pattern on the lower side of the ceiling.
2. Description of the Prior Art
Grid systems of the kind referred to above are marketed by Ecophon AB, Hyllinge, Sweden, under the trade mark Focus D. The main runners in this prior art grid system are of a reliable construction and are used also in other grid systems marketed by Ecophon AB. They are manufactured in large quantities, which keeps the price of such runners at a low level. The apertures in the web of the T-profile are punched with great accuracy. The spacers comprise L-profiles forming slots in one flange thereof to receive the main runners therein. Each spacer spans the distance between two adjacent main runners only and is located in an arbitrary displaced position along the main runners. No means are provided in order to fix the spacers in the position that has been chosen.
U.S. Pat. No. 4,089,146 discloses a grid system for a suspended ceiling with asymmetric main runners comprising rather elaborate box profiles. The main runners each form a flange for supporting a tile at one edge thereof and are combined with separate cross bars supporting the tile at two other edges thereof. Spacers of V-shaped cross section are mounted on the main runners receiving the box profile in a notch in the spacer.
3. Problem Involved
Prior art grid systems of the kind referred to above do not provide the rigidity that is necessary in order to maintain by accuracy the regularity and the right-angled shape of the rectangular pattern formed by the tiles. It follows that the lines formed at the joints between adjacent tiles at the lower side of the ceiling may vary in width and linearity, and that the tiles eventually may be slightly displaced in relation to each other after mounting, which may afford to the ceiling an unpleasant appearance.